package string;
/** StringBuilder的演示　*/
public class StringBuilderDemo {
    public static void main(String[] args) {
        String str = "好好学习Java";
        //复制str的内容到builder中----好好学习Java
        StringBuilder builder = new StringBuilder(str);

        //append():追加内容---在末尾追加
        builder.append("，为了找个好工作");
        System.out.println(builder); //好好学习Java，为了找个好工作

        //replace():替换部分内容(含头不含尾)
        builder.replace(9,16,"就是为了改变世界");
        System.out.println(builder); //好好学习Java，就是为了改变世界

        //delete():删除部分内容(含头不含尾)
        builder.delete(0,8); //删除下标为0到7的
        System.out.println(builder); //，就是为了改变世界

        //insert():插入内容
        builder.insert(0,"活着");
        System.out.println(builder); //活着，就是为了改变世界







        /*
        //StringBuilder的创建方式:
        StringBuilder builder1 = new StringBuilder(); //空字符串
        StringBuilder builder2 = new StringBuilder("abc"); //abc串

        //String和StringBuilder互转:
        String str = "abc";
        StringBuilder builder3 = new StringBuilder(str); //abc串
        String str2 = builder3.toString();
         */
    }
}

























